Electronic stethoscope with idealized bell and idealized diaphragm modes

Abstract

An electronic stethoscope emulates the frequency response of a standard acoustical stethoscope in both bell and diaphragm modes, while providing additional features attainable only with an electronic stethoscope, such as signal amplification, noise reduction, wider bandwidth, and mode selection. The electronic stethoscope includes spectrally separate idealized diaphragm and idealized bell modes. The idealized diaphragm mode and the idealized bell mode each include emphasized passbands and de-emphasized passbands. The emphasized passbands are spectrally separate. In addition, the electronic stethoscope also includes a wideband mode, which permits the user to hear high frequency sounds such as those associated with mechanical heart valves, lung sounds, and the like.

We claim: 
     
       1. An electronic stethoscope, comprising: microphone means for sensing sounds of interest produced within a patient's body;   filter means, adapted to receive the sounds of interest, for providing at least two spectrally separate operational modes, wherein the filter means includes: bell mode means for receiving the sounds of interest and for producing therefrom a bell mode overall passband including a first emphasized passband from about 20-100 Hz and first de-emphasized passband from about 100-500 Hz, wherein a gain of the first emphasized passband is greater than a gain of the first de-emphasized passband by about 15 dB or less; and   diaphragm mode means for receiving the sounds of interest and for producing therefrom a diaphragm ode overall passband including a second de-emphasized passband from about 20-200 Hz and a second emphasized passband from about 200-500 Hz, wherein a gain of the second emphasized passband is greater than a gain of the second de-emphasized passband by about 15 dB or less;     mode selection means for selecting between the operational modes; and   speaker means for reproducing the filtered sounds for perception by a user.   
     
     
       2. The electronic stethoscope of claim 1 wherein the filter means adapted to provide the operational modes such that the electronic stethoscope has the sound of an acoustic stethoscope. 
     
     
       3. The electronic stethoscope of claim 1 further including a user adjustable volume control, wherein in at least one volume setting, the output level of the reproduced sounds is about equivalent to that of a traditional acoustic stethoscope. 
     
     
       4. The electronic stethoscope of claim 1 wherein the filter means is further for providing a wideband operational mode and wherein the filter means further includes wideband mode means for receiving the sounds of interest and for producing therefrom a wideband passband from about 20-2000 Hz. 
     
     
       5. The electronic stethoscope of claim 1 wherein the gain of the first emphasized passband is greater than the gain of the first de-emphasized passband by about 10 dB. 
     
     
       6. The electronic stethoscope of claim 1 wherein the gain of the second emphasized passband is greater than the gain of the second de-emphasized passband by about 10 dB. 
     
     
       7. An electronic stethoscope, comprising: microphone means for sensing sounds of interest produced within a patient's body;   bell mode filter means adapted to receive the sounds of interest for providing an idealized bell mode overall passband filter from about 20-500 Hz when in a bell operational mode, the bell mode overall passband filter including at least a first emphasized passband from about 20-100 Hz and a first de-emphasized passband from about 100-500 Hz, wherein a gain of the first emphasized passband is greater than a gain of the first de-emphasized passband by about 15 dB or less; and   diaphragm mode filter means adapted to receive the sounds of interest for providing an idealized diaphragm mode overall passband filter from about 20-500 Hz when in a diaphragm operational mode, the diaphragm mode overall passband filter including at least a second emphasized passband from about 200-500 Hz and a second de-emphasized passband from about 20-200 Hz, wherein a gain of the second emphasized passband is greater than a gain of the second de-emphasized passband by about 15 dB or less;   mode selection means for selecting between at least the bell and diaphragm operational modes; and   speaker means for reproducing the filtered sounds for perception by a user.   
     
     
       8. The electronic stethoscope of claim 7 wherein the stethoscope further includes a wideband mode filter adapted to receive the sounds of interest, the wide band mode filter providing a wideband mode overall passband from about 20-2000 Hz. 
     
     
       9. The electronic stethoscope of claim 7 wherein the reproduced sounds are input into a computerized data acquisition system. 
     
     
       10. The electronic stethoscope of claim 7 wherein the stethoscope is powered by a AAA battery. 
     
     
       11. The electronic stethoscope of claim 7 wherein the filter means comprises digital filters. 
     
     
       12. The electronic stethoscope of claim 7 wherein the filter means comprises analog filters. 
     
     
       13. The electronic stethoscope of claim 7 further including mode indicating means for visually indicating the selected operational mode. 
     
     
       14. The electronic stethoscope of claim 7 further including a user adjustable volume control. 
     
     
       15. The electronic stethoscope of claim 14 wherein in at least one volume setting, the output level of the reproduced sounds is about equal to that of a traditional acoustic stethoscope.